# frozen_string_literal: true
module Blacklight::SearchContext
  extend ActiveSupport::Concern

  # The following code is executed when someone includes blacklight::catalog::search_session in their
  # own controller.
  included do  
    helper_method :current_search_session, :search_session

  end

  module ClassMethods
    # Save the submitted search parameters in the search session
    def record_search_parameters opts = { only: :index}
      before_action :current_search_session, opts
    end
  end

  protected

  # sets up the session[:search] hash if it doesn't already exist
  def search_session
    session[:search] ||= {}
  end

  # The current search session
  def current_search_session

    @current_search_session ||= if start_new_search_session?
      find_or_initialize_search_session_from_params search_state.to_h
    elsif params[:search_context].present?
      find_or_initialize_search_session_from_params JSON.load(params[:search_context])
    elsif params[:search_id].present?
      begin
        # TODO: check the search id signature.
        searches_from_history.find(params[:search_id])
      rescue ActiveRecord::RecordNotFound
        nil
      end
    elsif search_session['id']
      begin
        searches_from_history.find(search_session['id'])
      rescue ActiveRecord::RecordNotFound
        nil
      end
    end

    search_session['id'] = @current_search_session.id if @current_search_session

    @current_search_session
  end

  ##
  # If the current action should start a new search session, this should be
  # set to true
  def start_new_search_session?
    false
  end

  def find_or_initialize_search_session_from_params params
    params_copy = params.reject { |k,v| blacklisted_search_session_params.include?(k.to_sym) or v.blank? }

    return if params_copy.reject { |k,v| [:action, :controller].include? k.to_sym }.blank?

    saved_search = searches_from_history.find { |x| x.query_params == params_copy }

    saved_search ||= Search.create(query_params: params_copy).tap do |s|
      add_to_search_history(s)
    end
  end

  # Add a search to the in-session search history list
  def add_to_search_history search
    session[:history] ||= []

    session[:history].unshift(search.id)

    if session[:history].length > blacklight_config.search_history_window
      session[:history] = session[:history].slice(0, blacklight_config.search_history_window )
    end
  end

  # A list of query parameters that should not be persisted for a search
  def blacklisted_search_session_params
    [:commit, :counter, :total, :search_id, :page, :per_page]
  end

  # calls setup_previous_document then setup_next_document.
  # used in the show action for single view pagination.
  def setup_next_and_previous_documents
    if search_session['counter'] and current_search_session
      index = search_session['counter'].to_i - 1
      response, documents = get_previous_and_next_documents_for_search index, ActiveSupport::HashWithIndifferentAccess.new(current_search_session.query_params)

      search_session['total'] = response.total
      @search_context_response = response
      @previous_document = documents.first
      @next_document = documents.last
    end
  rescue Blacklight::Exceptions::InvalidRequest => e
    logger.warn "Unable to setup next and previous documents: #{e}"
  end
end